The Geologic Record is divided into Eons, Eras, Periods, and Epochs. There are just two Eons: Phanerozoic (0-542 million years ago (MYA) and the
Precambrian (542 - 4600 MYA) Now, going backwards:
+ Cenozoic Era = 0-66 MYA
++ Neogene Period = 0-23 MYA
+++ Holocene Epoch = 0-.01 MYA
+++ Pleistocene Epoch = .01-1.8 MYA
+++ Pliocene Epoch = 1.8-5 MYA
+++ Miocene Epoch = 5-23 MYA
++ Paleogene Period = 23-66 MYA
+++ Oligocene Epoch = 23-34 MYA
+++ Eocene Epoch = 34-56 MYA
+++ Paleocene Epoch = 56-66 MYA
+ Mesozoic Era = 66-251 MYA
++ Cretaceous Period = 66-146 MYA
++ Jurassic Period = 146-200 MYA
++ Triassic Period = 200-251 MYA
+ Paleozoic Era = 251-542 MYA
Let's stop here. Hopefully I've got them all spelled right. It keeps going until you get to 4.6 billion years ago. Couple of points.
+ The dividing line between the Mesozoic Cretaceous and the Cenozoic Paleocene is often called the "K/T Barrier" which stands for
"Cretaceous/Tertiary" where "Tertiary" refers to the Cenozoic Era. This is when the big comet hit and killed all the dinos
+ Quaternary is composed of the Holocene, the Pleistocene, and part of the Pliocene Epochs.
+ The Oligocene is an EPOCH which is part of the Paleogene PERIOD which is a part of the Cenozoic ERA which is a part of the Phanerozoic EON.
+ Some of the names and dates are a bit fluid, so don't be surprised if you find slightly different dates and names in different places. This one is
originally from "A Geologic Timescale 2004" Cambridge University Press, as reported in "Historical Geology, 6th edition." which is a textbook I just
happen to be reading through right now.
edit on 7/19/2018 by schuyler because: (no reason given)